Abstract # 2178 Poster # 39:

Scheduled for Thursday, June 21, 2007 05:00 PM-07:00 PM: Session 7 (South Main Hall) Poster Presentation

Bone Mineral Density and Trabecular Structure in Rhesus Macaque (Macaca mulatta) Lumbar Vertebrae: A Comparison of Micro-CT and DEXA

J. E. Turnquist1, A. M. Cerroni2, K. J. Faccia3,4, S. K. Boyd3,5 and B. Hallgrimsson3,6
1University of Puerto Rico School of Medicine, Department of Anatomy, PO Box 365067, San Juan, PR 00936-5067, USA, 2Department of Anthropology, University of Toronto, 3Bone and Joint Institute, 4Department of Archaeology, 5Department of Mechanical Engineering, 6Department of Cell Biology and Anatomy, University of Calgary
     Naturally occurring osteoporosis is associated with increased fracture risk, including vertebral crushing. Bone Mineral Density (BMD) measured using Dual-Energy X-ray Absorptiometry (DEXA) is the established standard for defining osteoporosis and relative fracture risk. This method, however, examines only bone quantity and not trabecular bone architecture / quality which are also implicated in increased fracture susceptibility. This study compares data from DEXA and micro-CT to assess the relative fracture risk predictability of each. The last lumbar vertebral body, from 36 female free-ranging rhesus macaques (5.4 to 23.7 years) from Cayo Santiago, PR was examined. Results showed a 0.80 correlation between areal BMD (g/cm2) from DEXA (Lunar) and the closest equivalent volumetric micro-CT (SCANCO) value (mg/cm3). Multivariant analysis [a=0.05] of micro-CT trabecular structure and architecture revealed bone density is most highly correlated with trabecular thickness (0.94) and bone volume ratio (0.99). Correlation between bone density and other bone architectural elements, e.g., connectivity, bone surface ratio, and number of trabeculae, was not significant. Neither morphology nor BMD revealed significant differences between last vertebrae of individuals with or without fractures elsewhere in the vertebral column. The results of this study show DEXA as a less perfect measure of actual bone density than micro-CT which also provides insight into trabecular structure to help assess osteoporotic status and relative fracture risk. [Support: University of Calgary, University of Toronto, UPR RR03640 & RR03051]